Is a polygraph admissible in civil court?

I am not your lawyer. This is not legal advice. But a quick-and-dirty online check of Texas law appears to indicate that the answer is “no.” The Texas Constitution and Statutes seem to be silent on the point, but see In the Interest of B.N.B., 246 S.W.3d 403, 410 (Tex. App.—Dallas 2008, no pet.); Izaguire v. Cox, 100108 TXCA10, 10-07-00318 (Tex. App.—Tenth Distr. 2008); Posner v. Dallas County Child Welfare Unit of Tex. Dep’t of Human Servs., 784 S.W.2d 585, 588 (Tex. App.—Eastland 1990, writ denied) (same).

You should, of course, consult with knowledgeable local counsel.